97th DOG Annual Meeting 1999

V176

SHORT TERM ELECTRORETINOGRAPHICAL CHANGES FOLLOWING PANRETINAL ARGON LASER PHOTOCOAGULATION IN RABBIT'S RETINA

A. Papp, L. Imre, I. Süveges


Purpose: Panretinal photocoagulation is a well known, routine therapeutic procedure of several eye diseases. The character, the degree and the cause of development of the electroretinographical changes following the photocoagulation is not well cleared up. Our purpose was the recognition of the functional changes of the retina following panretinal photocoagulation with electrophysiological methods.

Methods: 12 eyes of 6 rabbits were treated with indirect binocular laser ophthalmoscope: 6 right eyes with argon blue-green, 6 left eyes with argon green. We applied on an average 1200 laser burns per eye. Using different stimulation we measured the photopic and scotopic answers before, directly after, 1, 3, and 7 days and 1 month after the treatment.

Results: Using the 0,25log SF stimulus we found significant decrease in the amplitudes directly after the laser treatment, which showed a similar pattern on the 1st and the 3rd day, but on the 7th day we observed an increasing tendency in the amplitudes. One month after the treatment the amplitudes were near to the pre-treatment values. Stimulating with standard flash we found quite similar tendencies, after the 7th day the amplitudes begun to rise. Under photopic conditions we observed a definite drop in the amplitudes as well, which showed a continuous increasing tendency. The implicit time values increased after treatment, their maximal values were measured generally on the 1st day, then they showed a slow regression. Considerable differences between the two eyes could be found only in the photopic a and b wave implicit time values, we found a smaller increase of implicit time in the eyes treated with argon green.

Conclusions: The electroretinographical changes (implicit time, amplitude) following the laser treatment showed an improving tendency from the 7th day. The above described electrophysiological changes show the damage of the blood-retina barrier due to the destructive treatment, which are nearly reversible after the pigmentation of the laser burns.

1st Dept. of Ophthalmology, Semmelweis Medical University Tömo str. 25-29 H-1083, Budapest, Hungary


Back